/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.hadoop.hbase.regionserver;

import org.apache.hadoop.hbase.HBaseInterfaceAudience;
import org.apache.hbase.thirdparty.com.google.common.base.Preconditions;
import org.apache.yetus.audience.InterfaceAudience;
import org.apache.hadoop.hbase.client.Mutation;
import org.apache.hadoop.hbase.wal.WALEdit;

/**
 * Wraps together the mutations which are applied as a batch to the region and their operation
 * status and WALEdits.
 *
 * @param T Pair&lt;Mutation, Integer&gt; pair of Mutations and associated rowlock ids .
 * @see org.apache.hadoop.hbase.coprocessor.RegionObserver#preBatchMutate(
 *org.apache.hadoop.hbase.coprocessor.ObserverContext, MiniBatchOperationInProgress)
 * @see org.apache.hadoop.hbase.coprocessor.RegionObserver#postBatchMutate(
 *org.apache.hadoop.hbase.coprocessor.ObserverContext, MiniBatchOperationInProgress)
 */
@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.COPROC)
public class MiniBatchOperationInProgress<T> {
    private final T[] operations;
    private Mutation[][] operationsFromCoprocessors;
    private final OperationStatus[] retCodeDetails;
    private final WALEdit[] walEditsFromCoprocessors;
    private final int firstIndex;
    private final int lastIndexExclusive;

    private int readyToWriteCount = 0;
    private int cellCount = 0;
    private int numOfPuts = 0;
    private int numOfDeletes = 0;


    public MiniBatchOperationInProgress(T[] operations, OperationStatus[] retCodeDetails, WALEdit[] walEditsFromCoprocessors, int firstIndex,
            int lastIndexExclusive, int readyToWriteCount) {
        Preconditions.checkArgument(readyToWriteCount <= (lastIndexExclusive - firstIndex));
        this.operations = operations;
        this.retCodeDetails = retCodeDetails;
        this.walEditsFromCoprocessors = walEditsFromCoprocessors;
        this.firstIndex = firstIndex;
        this.lastIndexExclusive = lastIndexExclusive;
        this.readyToWriteCount = readyToWriteCount;
    }

    /**
     * @return The number of operations(Mutations) involved in this batch.
     */
    public int size() {
        return this.lastIndexExclusive - this.firstIndex;
    }

    /**
     * @param index
     * @return The operation(Mutation) at the specified position.
     */
    public T getOperation(int index) {
        return operations[getAbsoluteIndex(index)];
    }

    /**
     * Sets the status code for the operation(Mutation) at the specified position.
     * By setting this status, {@link org.apache.hadoop.hbase.coprocessor.RegionObserver}
     * can make HRegion to skip Mutations.
     *
     * @param index
     * @param opStatus
     */
    public void setOperationStatus(int index, OperationStatus opStatus) {
        this.retCodeDetails[getAbsoluteIndex(index)] = opStatus;
    }

    /**
     * @param index
     * @return Gets the status code for the operation(Mutation) at the specified position.
     */
    public OperationStatus getOperationStatus(int index) {
        return this.retCodeDetails[getAbsoluteIndex(index)];
    }

    /**
     * Sets the walEdit for the operation(Mutation) at the specified position.
     *
     * @param index
     * @param walEdit
     */
    public void setWalEdit(int index, WALEdit walEdit) {
        this.walEditsFromCoprocessors[getAbsoluteIndex(index)] = walEdit;
    }

    /**
     * @param index
     * @return Gets the walEdit for the operation(Mutation) at the specified position.
     */
    public WALEdit getWalEdit(int index) {
        return this.walEditsFromCoprocessors[getAbsoluteIndex(index)];
    }

    private int getAbsoluteIndex(int index) {
        if(index < 0 || this.firstIndex + index >= this.lastIndexExclusive) {
            throw new ArrayIndexOutOfBoundsException(index);
        }
        return this.firstIndex + index;
    }

    /**
     * Add more Mutations corresponding to the Mutation at the given index to be committed atomically
     * in the same batch. These mutations are applied to the WAL and applied to the memstore as well.
     * The timestamp of the cells in the given Mutations MUST be obtained from the original mutation.
     * <b>Note:</b> The durability from CP will be replaced by the durability of corresponding mutation.
     *
     * @param index         the index that corresponds to the original mutation index in the batch
     * @param newOperations the Mutations to add
     */
    public void addOperationsFromCP(int index, Mutation[] newOperations) {
        if(this.operationsFromCoprocessors == null) {
            // lazy allocation to save on object allocation in case this is not used
            this.operationsFromCoprocessors = new Mutation[operations.length][];
        }
        this.operationsFromCoprocessors[getAbsoluteIndex(index)] = newOperations;
    }

    public Mutation[] getOperationsFromCoprocessors(int index) {
        return operationsFromCoprocessors == null ? null : operationsFromCoprocessors[getAbsoluteIndex(index)];
    }

    public int getReadyToWriteCount() {
        return readyToWriteCount;
    }

    public int getLastIndexExclusive() {
        return lastIndexExclusive;
    }

    public int getCellCount() {
        return cellCount;
    }

    public void addCellCount(int cellCount) {
        this.cellCount += cellCount;
    }

    public int getNumOfPuts() {
        return numOfPuts;
    }

    public void incrementNumOfPuts() {
        this.numOfPuts += 1;
    }

    public int getNumOfDeletes() {
        return numOfDeletes;
    }

    public void incrementNumOfDeletes() {
        this.numOfDeletes += 1;
    }
}
